This invention relates generally to testing of circuit board connectors. In particular, it relates to self-testing of connectors that are electrically connected to outputs an integrated circuit located on the circuit board.
Integrated circuits typically include a large amount of electronic circuitry. The electronic circuitry generally includes an even larger number of electrical interconnections. The interconnections can fail, causing the electronic circuitry to operate improperly. Therefore, the electronic circuitry including the interconnections must be tested to ensure that the electronic circuitry is operable and is properly connected.
Many integrated circuits include built-in self-testing. Built-in self-testing of the circuitry of integrated circuits generally includes the integrated circuits internally testing electronic connections within the integrated circuit without the requirement of external test equipment. As a result, built-in self-testing reduces the cost of manufacturing integrated circuits because built-in self-testing eliminates the purchase, programming and design of external test equipment.
Integrated circuits are typically interconnected to circuit boards which are in turn connected to other circuit boards. Outputs and inputs of the integrated circuits are connected to conductive traces on the circuit boards. The conductive traces are electrically connected to connectors that provide a conductive interconnection to the other circuit boards.
Built-in self-testing can test the integrity of electronic circuits located within an integrated circuit, but cannot test the integrity of interconnections between the integrated circuits and the connectors of the circuit boards without the presence of additional external test fixtures. Therefore, the connectors must be tested separately, requiring separate test equipment. In addition, time for testing the connectors must be allocated during manufacture of the circuit boards.
It is desirable to have a system and method for built-in self-testing of connectors of a circuit board that are electrically connected to the inputs and outputs of an integrated circuit.
The present invention is a system and method for built-in self-testing of connectors of a circuit board that is electrically connected to the inputs and outputs of an integrated circuit.
A first embodiment of this invention includes an integrated circuit self-testing system. The integrated circuit self-testing system includes a circuit board and an integrated circuit connected to the circuit board. The integrated circuit includes an output. A connector is attached to the circuit board. A conductive trace of the circuit board electrically connects the output of the integrated circuit to the connector. The conductive trace includes a first section extending between the output of the integrated circuit and the connector of the circuit board, and a second section extending beyond the connector. The integrated circuit includes a pulse generator, that generates a pulsed voltage potential at the output. The integrated circuit further includes a pulse transient detector that detects transients in the voltage potential of the output due to a reflected pulse voltage potential received at the output, thereby indicating whether the connector is properly connected to the conductive trace. It is to be understood that the invention can and is generally extended to include many connectors connected to many outputs of the integrated circuit through many conductive traces.
A second embodiment of this invention is similar to the first embodiment. The pulse generator of the second embodiment includes a digital logic gate that drives the output of the integrated circuit from a low voltage potential to a high voltage potential.
A third embodiment of this invention is similar to the second embodiment. The pulse transient detector of third embodiment includes a peak detector capacitor in which a final voltage potential of the peak detector capacitor is dependent upon the output of the integrated circuit receiving a negative transient pulse.
A fourth embodiment of this invention is similar to the third embodiment. The pulse transient detector of the fourth embodiment further includes a peak detector diode that conducts charge from the peak detector capacitor when the output of the integrated circuit receives a negative transient pulse.
A fifth embodiment of this invention is similar to the fourth embodiment, but the pulse transient detector of the fifth embodiment further includes an analog to digital converter connected to the peak detector capacitor, the analog to digital converter detecting the voltage potential of the peak detector capacitor.
Another embodiment of the invention includes a method of self-testing connectors that are connected to a circuit board. At least one of the connectors is electrically connected to an output of an integrated circuit that is attached to the circuit board through a conductive trace. The conductive trace includes a first section extending between the output of the integrated circuit and the connector of the circuit board, and a second section extending beyond the connector. The method includes generating a pulsed voltage signal at the output of the integrated circuit, and detecting transients in the voltage potential of the output due to a reflected pulse voltage potential received at the output, thereby indicating whether the connector is properly connected to the conductive trace.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.